Intermitten miss

PARAROB

MEMBER
2008 FORD ESCAPE
3.0L
6 CYL
4WD
AUTOMATIC
80,000 MILES

Drives normal then a miss or jumping on light acceleration step down and it clears up then I get a popping sound from the air box on idle and a miss sound from exhaust with a rough or low idle. No codes, replaced gas and air filter and o2 sensor because of code before.

Thursday, June 11th, 2020 AT 10:29 AM

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

This sounds like a sticking valve in the head. Do you have a vacuum gauge that we can hook to the engine to see if the needle flutters when you are seeing this issue?

Basically the valve is responsible for allowing air in and out of the engine. If we have a valve sticking then it will allow air in and out of the cylinder at the wrong time causing the issue you are seeing.

We can try a compression test but sometimes sticking valves do not show up on compression tests.

https://www.2carpros.com/articles/how-to-test-engine-compression

The best way to find this is to hook up a vacuum gauge so if you don't have one, you can either rent one from a parts store or just purchase one. They are normally less then $20.00.

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Thursday, June 11th, 2020 AT 5:11 PM